This research will review existing approaches to the estimation of the state of wear of an automotive damper, with the aim of developing a methodology for a quick and effective diagnostic procedure that could be carried out in any repair facility. It has always been desirable to leave the shock absorber in place at the time of such testing, and there are three general procedures that claim to be effective at determining damper wear. The general procedures are: to remove the shock and perform a dynamometer test, to leave the shock in place and vibrate the tire at known frequencies, and the last is to push on one corner at a time and observe the oscillations. This research investigates a method of controlling a short drop of each corner of the vehicle while measuring the acceleration. The acceleration data is then analyzed with the aim of estimating the decay rate of the resulting oscillation, which is known to be related to the damping ratio of the suspension system. The rate of decay, quantified by the damping ratio, is then used to infer the condition of the vehicle’s damper. Multiple tests were conducted with shock absorbers of different degrees of wear to assure the capability of this methodology. Also, tests were run to examine the effects of spurious inputs to the test procedure, such as low tire pressure and the affect a failed damper on the opposite end of the axle has on the test results for a new damper. This thesis reviews the state of the art, describes the methodology and presents experimental validation of a new concept.
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